[PATCH 6.14 017/731] cpufreq/amd-pstate: Modify the min_perf calculation in adjust_perf callback

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>

[ Upstream commit 6ceb877d5cecd5417d63239bf833a1cd5f8f271c ]

Instead of setting a fixed floor at lowest_nonlinear_perf, use the
min_limit_perf value, so that it gives the user the freedom to lower the
floor further.

There are two minimum frequency/perf limits that we need to consider in
the adjust_perf callback. One provided by schedutil i.e. the sg_cpu->bw_min
value passed in _min_perf arg, another is the effective value of
min_freq_qos request that is updated in cpudata->min_limit_perf. Modify the
code to use the bigger of these two values.

Signed-off-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://lore.kernel.org/r/20250205112523.201101-4-dhananjay.ugwekar@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Stable-dep-of: 426db24d4db2 ("cpufreq/amd-pstate: Add missing NULL ptr check in amd_pstate_update")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/cpufreq/amd-pstate.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 313550fa62d41..17595a2454e1c 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -672,7 +672,7 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
 				   unsigned long capacity)
 {
 	unsigned long max_perf, min_perf, des_perf,
-		      cap_perf, lowest_nonlinear_perf;
+		      cap_perf, min_limit_perf;
 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 	struct amd_cpudata *cpudata;
 
@@ -684,20 +684,20 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
 	if (policy->min != cpudata->min_limit_freq || policy->max != cpudata->max_limit_freq)
 		amd_pstate_update_min_max_limit(policy);
 
-
 	cap_perf = READ_ONCE(cpudata->highest_perf);
-	lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf);
+	min_limit_perf = READ_ONCE(cpudata->min_limit_perf);
 
 	des_perf = cap_perf;
 	if (target_perf < capacity)
 		des_perf = DIV_ROUND_UP(cap_perf * target_perf, capacity);
 
-	min_perf = READ_ONCE(cpudata->lowest_perf);
 	if (_min_perf < capacity)
 		min_perf = DIV_ROUND_UP(cap_perf * _min_perf, capacity);
+	else
+		min_perf = cap_perf;
 
-	if (min_perf < lowest_nonlinear_perf)
-		min_perf = lowest_nonlinear_perf;
+	if (min_perf < min_limit_perf)
+		min_perf = min_limit_perf;
 
 	max_perf = cpudata->max_limit_perf;
 	if (max_perf < min_perf)
-- 
2.39.5